Organic materials, such as organic semiconductors, have become important materials in many microelectronic applications—from high-performance electronics systems to flat-panel displays based on organic-light-emitting-diodes (OLEDs).
Unfortunately, organic materials are exemplary of a class of sensitive materials that are difficult to pattern photolithographically due to the fact that they are incompatible with many of the required chemicals. As a result, alternative patterning methods have been developed for such sensitive materials, such as stamp-based lithography, direct patterning via deposition through a shadow mask, and special ultraviolet active systems used in multistage patterning approaches. In some applications, such as OLED manufacture, shadow-mask-based patterning has become the de facto standard. Feature sizes obtainable using shadow mask patterning are typically limited to relatively large dimensions (e.g., several microns to tens of microns), however, due to the fact that the deposited material tends to spread laterally after passing through the shadow mask-referred to as “feathering.” Furthermore, stamp-based lithography and active approaches have been difficult to scale and remain somewhat unreliable.
In the hope of enabling integration into mainstream integrated-circuit manufacturing, alternative approaches, such as photoresists based on fluorinated solvents have been explored. Unfortunately, fluorinated resists still suffer from significant limitations in feature resolution, as well as other issues.
Feature size remains a limiting factor in the development of practical approaches to the fabrication of many organic-material-based devices. For example, an organic electrochemical transistor (OECT) requires a very small gate length to achieve fast device speeds, while high-resolution OLED displays require large arrays of densely packed, very small light-emitting regions.
The need for a practical method for patterning sensitive materials with fine, preferably sub-micron, dimensions remains, as yet, unmet in the prior art. The development of such a method would unlock the potential for many sensitive materials, such as organic materials, organic semiconductors, biomolecular materials, and the like, across many application areas.